The present invention relates to improvements in plastic sliders for opening and closing plastic reclosable fasteners or zippers on plastic bags and the like and the method of assembling a multi-part plastic slider as a unit with a profiled plastic reclosable fastener on the plastic bags.
Plastic zippers with plastic sliders are well known in the art. The type of plastic zippers to which the present invention relates have profiles that include a pair of male and female fastener elements in the form of reclosable interlocking rib and groove elements with a slider for opening and closing the rib and groove elements. In the manufacture of plastic-film bags, a pair of these male and female fastener elements extend along the mouth of the bag and these male and female elements are adapted to be secured in any suitable manner to the flexible walls of the plastic-film bags.
The sliders for opening or closing the reclosable fasteners are essentially U-shaped and are adapted to be assembled with the zipper by threading them onto the end of the zipper or by a relative transverse maneuver. To facilitate the transverse maneuver, some of the sliders have been provided with folding sidewalls and others have been assembled on the zipper from multiple parts. In some instances, the multiple parts of the plastic slider have been ultrasonically welded together and in other instances the multiple parts of the slider have been constructed to be snapped together. However, in each of these prior art multi-part plastic sliders the various parts have been assembled together in a direction transverse to the axis of the zipper. Examples of patents showing multi-part plastic sliders are shown in U.S. Pat. No. 5,007,142--Herrington, U.S. Pat. No. 5,007,143--Herrington and U.S. Pat. No. 5,020,194--Herrington et al.
It would be desirable to partially assemble the multi-part plastic slider into an assembly of partially joined parts for assembly as a unit with the zipper in a transverse direction.